1. Field of the Invention
The present invention relates to an endoscope apparatus suited to smoothly insert a flexible insertion portion into a bending body cavity.
2. Description of the Related Art
There has been widely available an endoscope which can observe organs in a body cavity and perform various types of treatments and procedures by inserting a flexible insertion portion into the body cavity such as a large intestine.
Considerable skill is required to smoothly insert an insertion portion into a body cavity complexly bending like a large intestine. An inexperienced operator may lose track of an insertion direction while inserting an insertion portion to a deep region, which may cause the operator to confront insertion difficulty. Accordingly, various types of proposals have been made to improve ease of inserting an insertion portion.
For example, Japanese Patent Laid-Open Publication No. 10-113396 describes a medical appliance propelling device which can guide a medical appliance up to a deep region of an organism canal easily and less invasively. The medical appliance propelling device has a rotary member rotatably disposed immediately before the distal end of a medical appliance. An outer-peripheral surface of the rotary member is formed with a rib slanting relative to an axial direction.
Accordingly, rotation of the rotary member permits a rotational force of the rotary member to be transformed into a propelling force by the rib. Then, the propelling force moves the medical appliance connected to the propelling device in a direction of the deep region.